To meet the demand for wireless data traffic having increased since deployment of 4G (4the-Generation) communication systems, efforts have been made to develop an improved 5G (5the-Generation) or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘beyond 4G network’ or a ‘post LTE system’.
The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems.
In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), reception-end interference cancellation and the like.
In the 5G system, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.
The introduction of Internet Protocol (IP) Multimedia Subsystem (IMS) has resulted in the increased usage of dedicated bearers, especially for voice calls and video calls. The frequent establishment and release of the bearers also accompanies with the modification, addition, or deletion of packet filters. These results in increased possibility of packet filter content conflicts in a User Equipment (UE) side. The 3rd Generation Partnership Project (3GPP) specification 24.301 describes about the scenario of packet filter mismatch or overlap (precedence, filter Identification (ID), or the like) and in such mismatch cases, the UE should accept the filters on a new bearer and delete the conflicting filters of the old bearer. The latter has to be updated to a network through a bearer resource modification request.
Further, the 3GPP specification states that the UE synchronizes the bearers with the network, after any local changes in the packet filters, through the bearer resource modification request. But, the specification does not describe the UE actions in case the bearer resource modification request is rejected by the network.
In response to the bearer resource modification request, the failure of the “Bearer Resource Modification” via “Bearer Resource Modification Reject” or “Evolved Packet System (EPS) Status” message from the network results in the bearer still being active on the UE side. Since the packet filters were deleted on the UE side (most of the times, all the filters related to the bearer), the bearer is no longer used to transmit any packets in the UE side. Since the bearer is still active in the UE side, the IMS client in UE continues to transmit data related to the bearer, which is in-turn not sent from a modem, due to deletion of the packet filter. The other possibility is that even if the packets are sent on the default bearer, the same will be dropped at a Primary Gateway (P-GW). This continues, till the release of the specific bearer by the network.
Further, if the UE transmit the Bearer Resource Modification Request to the network in order to release all the resources in the bearer, the network would normally respond by initiating a deactivation procedure for the context, but the network transmits Bearer Resource Modification Reject with cause value #31. The 3GPP specification does not specify what would be the correct UE action in such a case which means after the rejection the UE may have a useless EPS bearer context that cannot be released. This will lead to various problems in the UE such as data stall with respect to the bearer for which the UE has deleted all Traffic Flow Template (TFT) packet filters. If the bearer is related to audio call it will lead to call mute issue. If the bearer is related to the video call then the screen will be blank, or the like which degrades the user experience.
Consider a scenario: if a user of the UE initiates a Voice over Long Term Evolution (VoLTE) audio call, the network assigns the dedicated bearer for the audio which includes packet filters for the audio. Then UE upgrades the audio call to a video call. After upgrading the audio call to the video call, the network assigns dedicated bearer for the video which includes the packet filter for the video. Due to some changes on the network side, the network transmits a bearer resource modification request message for the audio bearer (includes new set of packet filters for the audio) to the UE. However, the packets received as part of bearer resource modification request message for the audio bearer has conflict (i.e., packet filter mismatch) with existing packet filters assigned for the video bearer. In such case, as per 3GPP specification, the UE accepts newly received packet filters and deletes the existing packet filters of the video bearer. The UE informs the same to the network through the bearer resource modification request with an OP CODE set as DELETE for the video bearer. If the network rejects the bearer resource modification request, the video bearer will not receive any data and video will be stuck since the packets filters for the video bearer has been deleted at the UE side. In such case, the video bearer will neither receive the video data nor is it released on the UE.
Consider another scenario: if the user of the UE initiates a VoLTE audio call. The network assigns the dedicated bearer for the audio which includes packet filters for the audio. The UE upgrades the audio call to the video call. The network assigns the dedicated bearer for the video which includes the packet filter for the video. Due to some changes on the network side, the network transmits the bearer resource modification request for the video bearer which includes new set of packet filters for the video. However, the packets received as part of bearer resource modification request for the video bearer has conflict (i.e., packet filter mismatch) with existing packet filters assigned for the audio bearer. In such case, as per 3GPP specification, the UE accepts the newly received packet filters and deletes the existing packet filters of the audio bearer. The UE informs the same to the network through the bearer resource modification request with the OP CODE set as DELETE for the audio bearer. The packet filter of the audio bearer is deleted at the UE. The deleted audio bearer information is not updated to the network as the network transmits the bearer resource modification reject message to the UE. Since the packet filters are deleted, the audio bearer will not receive any data and audio will be mute.
Consider another scenario: an Application “A” requests required Quality of Service (QoS) and the network assigns dedicated bearer for the Application “A”. Application “B” also requests required QoS, and the network assigns the dedicated bearer for the Application “B”. Due to some changes on the network side, the network transmits the bearer resource modification request for the Application “B” which includes new set of packet filters for the Application “A”. However, the packets received as part of the bearer resource modification request for the Application “A” have conflict (i.e., packet filter mismatch) with the existing packet filters assigned for the application “A”. In such case, as per 3GPP specification, the UE accepts newly received packet filters and deletes the existing packet filters of the Application “A”. The UE informs the same to the network through the bearer resource modification request with OP CODE set as DELETE for the audio bearer. If the network transmits the bearer resource modification reject message to the UE, the packet filter of Application “A” Bearer is deleted at the UE. The deleted packet filter is not updated to the network as the network sent the bearer resource modification reject to the UE. Thus, the Application “A” bearer will not receive any data and data stall will be observed for the Application “A”.
The above information is presented as background information only to help the reader to understand the present disclosure. Applicants have made no determination and make no assertion as to whether any of the above might be applicable as Prior Art with regard to the present application.